DataTableReader.IsDBNull Method
Gets a value that indicates whether the column contains non-existent or missing values.
Namespace: System.Data
Assembly: System.Data (in System.Data.dll)
Parameters
- ordinal
- Type: System.Int32
The zero-based column ordinal
Return Value
Type: System.Booleantrue if the specified column value is equivalent to DBNull; otherwise, false.
Implements
IDataRecord.IsDBNull(Int32)| Exception | Condition |
|---|---|
| ArgumentOutOfRangeException | The index passed was outside the range of 0 to FieldCount - 1. |
| DeletedRowInaccessibleException | An attempt was made to retrieve data from a deleted row. |
| InvalidOperationException | An attempt was made to read or access a column in a closed DataTableReader . |
The following example displays the contents of the column numbered 2 within the passed-in DataTableReader. If the value the column within a particular row is null, the code displays the text <NULL>. If the data within the column of the correct type, the example displays an error message for each row.
private static void PrintColumn(DataTableReader reader) { // Loop through all the rows in the DataTableReader while (reader.Read()) { if (reader.IsDBNull(2)) { Console.Write("<NULL>"); } else { try { Console.Write(reader.GetString(2)); } catch (InvalidCastException) { Console.Write("Invalid data type."); } } Console.WriteLine(); } }
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
